Question

Which division among plants has the simplest organisms?

Answer 1

Hint: As we are aware that the kingdom plantae is divided into main five divisions based on their differentiated/undifferentiated body, presence/absence of vascular bundles and with/without seeds named as Thallophyta, Bryophyta, Pteridophyta, Gymnosperms and Angiosperms.

Complete answer:
> As we already know that the kingdom plantae is divided into main five divisions named as Thallophyta, Bryophyta, Pteridophyta, Gymnosperms and Angiosperms. Based on the following criteria they are divided into these five divisions and these criteria are as follows: their differentiated/undifferentiated body, presence/absence of vascular bundles, with/without seeds and naked seeds/seeds inside fruits.
> Amongst these divisions the simplest organism is present in division Thallophyta. It is the lowest group of plants and has two main subdivisions- Algae and Fungi. It also includes bacteria, molds, slime and lichens.
> Their body structure is generally thalloid that means they do not possess roots but instead they have crude stems and leaves where roots are replaced by rhizoids which acts as an anchor.
> They do not have differentiation property and the reproductive structures are inconspicuous.
> Their vascular bundles for food and water conduction are also absent.
> They are called non-embryophytes as there is absence of embryo formation and they mainly grow in moist and wet places.
> Subdivision of Thallophyta includes Myxo Thallophyta which involves myxomycetes and the other one is Euthallophyta involving bacteria, fungi, algae and Lichens.
> They are autotrophic in nature and most of the members of this division make their own food except fungi which depends on other sources for their food.
> After performing photosynthesis, they consume the glucose immediately and the remaining glucose is converted into complex compounds like starch. So their reserve food is generally starch.
> Their cell wall is made up of cellulose, sex organs are simple and unicellular.

Hence the correct answer is Thallophyta is the simplest organism among plant divisions.

Note: Green algae Chlorella is used in prolonged space flights for food, oxygen and disposal of carbon dioxide and thus called ‘space alga’. Iodine is obtained from brown algae. Lichens are indicators of sulphur dioxide pollution.